Scoots, It sounds like your struggle is more than just PCS. Your anxiety can be a big contributor to your ups and downs. It sounds like you are trying some therapy. Brain nutrition helps the brain tolerate stress. Check out the Vitamins sticky at the top. Many of us find benefit to at least the basics, B-12, a B-50 Complex, D-3, Omega 3 fish oil, the anti-oxidants (C and E).

The anxious brain often needs more nutritional support. Caffeine can be a problem. MSG, added sugar, and such can be detrimental.

Good sleep is of paramount importance. If you go to bed anxious, you will not likely get good sleep. Finding a way to settle your mind before bed is helpful. I write down anything I need to do the next day so I don't obsess over it as I try to go to sleep. The act of writing down these tasks/issues is like setting them into a memory for tomorrow and helps many people let go of the thought.

The Serenity prayer has good logic and can help by just dividing the different issues, The things I can change, The things I can't, and wisdom to know the difference.

Your morning stiffness and other sensations suggest a neck issue. You may be able to resolve it by changing your sleep posture. Most people sleep with too much neck elevation. You should be trying to sleep with your head supported with your spine straight.